Another question for the metal workers if I may

[impala59]

After the immensely detailed response to my welding question, I have another if I may trouble you.

Working in mild (I'm guessing low carbon) steel, which is obviously easier to work, I wondered about "case hardening" There is a product called 'beta' I believe, that involves heating the work to 'cherry red' colour, dipping in the product, re-heating then quenching in oil or water. I am not really ready for this yet but looking forward to making stuff, I believe that hardening will be a necessary process for mild steel fabricated items. Will case hardening stiffen bar or rods for example? I am looking to make a couple of action bars for old pump guns, or should I look for higher carbon steel?

I therefore consult the PW oracle in my quest for basic knowledge and advice

Edited November 23, 2018 by impala59

[fatchap]

Case hardening will harden the outside of a steel bar for example to approx 00.03 , the more you repeat the process the deeper the hardening will go. One of the benefits of case hardening is the inside of the bar remains relatively soft so gives the bar a certain amount of flexibility. So for applications where the bar/rod slides against hardened surfaces, case hardening is ideal.

So to answer your question, no it wont stiffen a steel bar or rod. Best to opt for a higher carbon content and heat treat and temper.

Has its drawbacks, useless for knife making for instance.

[ditchman]

4 hours ago, fatchap said:

Case hardening will harden the outside of a steel bar for example to approx 00.03 , the more you repeat the process the deeper the hardening will go. One of the benefits of case hardening is the inside of the bar remains relatively soft so gives the bar a certain amount of flexibility. So for applications where the bar/rod slides against hardened surfaces, case hardening is ideal.

So to answer your question, no it wont stiffen a steel bar or rod. Best to opt for a higher carbon content and heat treat and temper.

Has its drawbacks, useless for knife making for instance.

this is the only and right answer.............heat treating and tempering is quite an easy process.........the stock bar you will buy will be in its soft state and will remain like that until you harden and temper................

be aware that the steel you buy .............it will either be steel that needs to be hardened in oil or water....you heat the steel until it loses its magnetic property...then quench it...clean it....and temperer it..........you will be able to temper it in your oven..............lots of simple imformation on the web......and the steel stockholder will be able to advise you on your purchase...........

but in essense fatchap is spot on...........

[la bala]

I have seen an old blacksmith guy case harden with salt, but I cant remember the colour of the heat.

[ditchman]

13 minutes ago, la bala said:

I have seen an old blacksmith guy case harden with salt, but I cant remember the colour of the heat.

you can do it with a carberising flame on oxy/acety...............and heat it up to orange heat and chuck it in old used black engine oil............

[la bala]

1 hour ago, ditchman said:

you can do it with a carberising flame on oxy/acety...............and heat it up to orange heat and chuck it in old used black engine oil............

old used black engine oil.. I got plenty of that.

[oowee]

What difference does it make if the oil is new or used? 

[ditchman]

1 hour ago, oowee said:

What difference does it make if the oil is new or used? 

if it comes from an engine....what makes it black is CARBON..........which is absorbed into the top layer of the red hot metal...and carbon is what turns iron into steel...generally the more carbon the harder the steel...unless there is another metal or alloy added to the molten iron........

iron has a lot of impurities in it so how the smiths improve it would be to heat it up and beat it to death squeezing the slag out of it and chucking it in the forge again...where it would absorb carbon....this would be done many times until the steel(now) was not throwing out any slag ..............usually in the old days charcoal made the best steel as it had very few impurites in it as apposed to coal..................

[oowee]

Thx for that. I remember putting something i made at school into oil to make it go black. 

[figgy]

Reading about a carburising flame took me back to my college days. 

I once oil blacked a blade in my teens to help stop it rusting.

Edited November 24, 2018 by figgy

[impala59]

Thank you gentlemen, I have much to learn, all of it interesting, if only I could get my youth back I think I would pay a great deal more attention to all this fascinating stuff!